It is known to provide multiple chamber flexible plastic containers for the separate storage of two substances, particularly medical substances, in a closed environment. Immediately before use, two or more chambers are placed in open communication for mixing of the substances, which are then typically delivered intravenously to a patient through an administration set secured to the container.
Such a container is shown in U.S. patent application Ser. No. 246,479, assigned to the assignee of the present invention, filed Mar. 23, 1981, to Richmond, et al. and now U.S. Pat. No. 4,465,488, which discloses a container made from flexible plastic sheeting separated into two individual chambers by means of a heat seal. A pathway is defined between the chambers by a flexible plastic tube having a frangible closure therein. The frangible closure is also shown in U.S. Pat. No. 4,340,049 to Munsch. When the frangible closure is broken, the two chambers are placed in fluid communication through the tube. The tube prevents the opened frangible closure from floating freely within one of the chambers. In addition, openings may be made in the tube to facilitate fluid flow upon opening of the closure.
Another multiple chamber, flexible-walled container suitable for the separate storage of two liquids is described in U.S. Pat. No. 4,396,383 to Hart, assigned to the assignee of the present invention.
Such multiple chamber medical fluid containers are especially useful for storing and mixing two supply solutions which when mixed form a single medical solution which itself is unsuitable for storage over extended time periods. Examples of medical substances which may not be combined until just prior to use include (1) dextrose solution and heparin and (2) dextrose solution and amino acids. There are many other medical liquids which may not be combined until just before delivery. to the patient.
The double chamber container is advantageous in that it provides a closed system for mixing the two liquids, eliminating the chance of contamination which would otherwise be present if the two medical substances were to be combined from two separate sources, such as might be done in a hospital pharmacy.
From the above it is readily apparent that because of the nature of the medical substances involved, virtually absolute separation of the two substances must be maintained during storage.
Flexible plastic containers such as the single chamber VIAFLEX.RTM. container sold by Travenol Laboratories, Inc. of Deerfield, Ill., provide a cost effective means for solution storage. Various plastics can be used, such as polyvinyl chloride sheeting. Two sheets of the plastic may be effectively sealed by such means as a heat seal to form the container. However, because of the criticality of preventing each of the medical substances from contacting the other during storage, it is especially desirable in multiple chamber containers to have a positive means for detecting the presence of any leak between the chambers caused by an improper seal between the flexible sheeting and the tube communicating between the chambers.